For centuries, leavened baked dough products have been prepared using yeast as a leavening agent. Dough ingredients such as flour, water, and optionally fat (e.g., oil), flavorants (e.g., salt or sweeteners), etc., are combined with yeast to form a dough mass. The dough is allowed to set for a time, typically at ambient temperature, to allow the yeast to produce carbon dioxide. During this step, known as “proofing,” carbon dioxide bubbles expand and leaven the dough to produce a lighter (“leavened”) raw and baked dough product. In addition to carbon dioxide and a leavened dough, the fermenting yeast also produces the pleasant aroma, flavor, and texture of a baked dough product that are often associated with freshly-baked bread that has been leavened by fermentation of yeast. Thus, yeast-fermenting a dough composition has been used for centuries to provide expected taste and aroma of a freshly-baked dough product.
In the past, preparing and baking the dough would not involve a freezing step. In modem times, though, bakeries and individual consumers greatly enjoy frozen doughs because of the convenience of allowing frozen doughs to be prepared, stored while frozen, and then thawed and cooked (e.g., baked) at a convenient time.
Frozen doughs should desirably produce a cooked dough product having properties comparable to cooked dough products that have been prepared and cooked without having been frozen. In practice, however, it is a substantial challenge to produce doughs that can be frozen for an extended period (e.g., in excess of 1 to 2 weeks for doughs that have been fermented prior to freezing, and from 3 to 6 months for doughs that have not been fermented prior to freezing) and then cooked to properties identical to doughs that are not stored frozen. This is especially true of doughs that are processed to allow yeast to ferment prior to freezing.
Yeast-leavened doughs that have been frozen for an amount of time may exhibit diminished stability (shelf life) in that leavening properties and baking quality of the dough may deteriorate after a few weeks of frozen storage. Deteriorated leavening properties and baking quality can mean extended proof times, deficient dough texture, or the inability to proof at all, any of which may result from a combination of yeast-related issues and physical damage to the structure of the gluten network of the dough.
Factors that can relate to shelf life of a frozen, unproofed dough product can include yeast viability and maintenance of yeast activity through frozen storage. An unproofed dough product, following frozen storage and upon thawing, must contain yeast that is sufficiently viable and intact to metabolize and generate carbon dioxide to leaven a dough during proofing. Yeast cells, being living organisms, may be susceptible to damage during freezing and frozen storage. Damaged yeast cells may lose their ability to produce carbon dioxide and to leaven (proof) a dough composition. In particular, it has been observed that yeast can become damaged if a yeast cell has become active during processing prior to freezing, meaning that the yeast has worked to metabolize ingredients of the dough to produce carbon dioxide, i.e., has fermented the dough. Still, fermentation prior to freezing is desired to achieve expected organoleptic properties of flavor, aroma, and texture. Consequently, there exists an ongoing need to achieve desired organoleptic qualities in a frozen unproofed dough, using fermentation of yeast prior to freezing, in a way that also achieves extended frozen shelf life with good proofing qualities of a dough upon thawing.